It is actually. I've seen hazy images recovered from your monitor by collecting the radio emissions of the cable. The signal traveled through windows, walls and an airgap of about 15 meters. The antenna used in that attack was only about half a meter long I think. I imagine you could put a much bigger antenna (or a dish) inside a van in the parking lot and spy on some analysts or something...
A good-sized antenna at range works, and so does a tiny device at close range! There are Van Eck listeners small enough to conceal completely that can still eavesdrop table-to-table at a cafe. The conference debut involved hiding one in a piece of pita bread, where it could sit right out in the open.
Jeez, at this point we might as well assume you can collect information from anything. I bet someone has made something that can restore the image on your screen by the vibrations on the windows that the sound of the power supply makes as the data flows in.
